Re: [PATCH] atomic: add atomic_inc_not_zero_hint()

Andi Kleen
2010-11-15T14:07:42Z

On Mon, Nov 15, 2010 at 07:57:10AM -0600, Christoph Lameter wrote:
> On Sat, 13 Nov 2010, Paul E. McKenney wrote:
>
> > On Fri, Nov 12, 2010 at 01:14:12PM -0600, Christoph Lameter wrote:
> > >
> > > prefetchw() would be too much overhead?
> >
> > No idea. Where do you believe that prefetchw() should be added?
>
> It is another way to get an exclusive cache line
> for situations like this. No need to give a hint.

prefetchw doesn't work on Intel (or rather is equivalent to prefetch),
for Intel you always need to explicitely write to get an exclusive
line.

-Andi

--
ak@linux.intel.com -- Speaking for myself only.